FIG. 1.

Diagram of the HCMV MIE promoter and regulatory control region. The enhancer between −550 and −39 has been investigated as a proximal enhancer between −300 and −39 and a distal enhancer between −550 and −300. The unique region has a repressive effect on the divergent UL127 promoter, unless sequences upstream of the TATA box are deleted. The modulator has a positive effect on the MIE promoter in transient transfection assays, but this effect was not detected with recombinant viruses. The MIE promoter and proximal enhancer to −223 used in this study are diagramed below.